4.4.62 SUBROUTINE ZTWGTC(INCR) : WeiGhT CALculation

This routine calculates the weight matrix of the track with hist stored in /ZTTRJ/ (filled by ZTFOLW) taking measurements, multiple scattering and geometry into account.

ARGUMENTS:

INPUT :

    INCR : if TRUE, this call is done in the process of transporting a
           weight matrix, rather than calculating it from scratch.

IMPLICIT INPUTS:

    from /ZTTRJ/ : R,Z,PHI,BETA : track parameters at intersection of each
                detector element; NPT : number of intersected elements;
                IORD : pointer into R etc ordered in increasing track-
                length; ITYP : cylinder/plane (1/2) and
                measurement/no measurement (+ve/-ve); JREF : the position
                of the reference surface intersection in rack-length ordering.
    if INCR = TRUE :
    From /MATRIX/ : WGT : weight matrix.

IMPLICIT OUTPUTS:

    to /MATRIX/ : WGT : weight matrix; IGEOM : geometry type of present
                  point (barrel/forward = 1/2)

CALLED BY :

ZTTRWT, calc. TRacK WeiGhT matrix (see 4.4.57).

CALLED ROUTINE(S):

ZTGEOC

(To switch between plane and cylindrical geometry.)

ZTPRPG

(To do geometrical propagation of errors.)

ZTMSCT

(To include multiple scattering.)

ZTWGAD

(To add contribution of measurement.)

VZERO,VADD,UCOPY

(CERNLIB routines.)

SIDE EFFECTS:

none

AUTHORS:

P. Billoir , LPNHE

CREATION DATE:

27-jul-1992

SUBROUTINE ZTGEOC(WG,IPT) * CALLED ROUTINE(S): * * none. *